Turn off the power to the freezer.
Locate the freezer's electrical access panel. A freezer's electrical access panel is generally located on the back of the unit, but the panel's location may vary depending on the appliance's brand and whether the freezer in question is part of a freezer/refrigerator combo.
Unscrew and open the electrical access panel and locate the capacitor. A freezer's capacitor is attached to the appliance's compressor.
Lay the metal end of your screwdriver over the two terminals on top of the capacitor. Because capacitors store electricity, you must discharge the stored electricity within the unit before touching it.
Disconnect the wiring connected to the capacitor. Disconnecting the wiring ensures that your multimeter will give you an accurate reading of the capacitor's condition.
Set your multimeter to "capacitance." Match up the multimeter's negative and positive leads with the capacitor's negative and positive terminals. Compare the microfarad reading the multimeter supplies with the microfarad rating noted on the capacitor itself. If the multimeter reads a significantly lower amount of microfarads than the capacitor should supply, you have a weak capacitor and should replace it soon.
Set your multimeter to test ohms if it lacks a capacitance setting. Hook up the positive and negative leads on the multimeter to the capacitor's negative and positive terminals. If the needle on the multimeter moves, this indicates that the capacitor is storing a charge. If the needle does not move, the capacitor is no longer functional.